Fix for my previous fix.

source/blender/editors/space_node/node_draw.c

@@ -609,6 +609,7 @@ static void do_node_internal_buttons(bContext *C, void *node_v, int event)
 		}			
 		else if(snode->treetype==NTREE_TEXTURE) {
 			WM_event_add_notifier(C, NC_TEXTURE|ND_NODES, snode->id);
+			ntreeTexUpdatePreviews(snode->nodetree);
 		}
 	}
 	

source/blender/editors/space_node/space_node.c

@@ -181,9 +181,6 @@ static void node_area_refresh(const struct bContext *C, struct ScrArea *sa)
 			if(scene->use_nodes)
 				snode_composite_job(C, sa);
 		}
-		else if(snode->treetype==NTREE_TEXTURE) {
-			ntreeTexUpdatePreviews(snode->nodetree);
-		}
 	}
 }